On my machines mains is supplied to the computer power supply. The computer is started and its power supply operates a relays coil. This relays coil operates the 240v coil of a contactor which powers the 24v PSUs which in turn powers the servos logic and the CSMIO.
I then have a combined Start/Stop button which powers the 24v coil of a contactor which supplies the power stage of my servo drives. This button also supplies 24v to a safety relay.
The E-Stop string is via this safety relay, it consists of an E-Stop button, limit switches and a NC relay controlled by fault signals from my servo drives.
The relay contacts on the safety relay handles such things as enables to drives (via Mach/CSMIO) , Halt signals, E-Stop to CSMIO ETC.
If a limit is hit or the E-Stop button or indeed a drive faults the relay will take away the halt signals from my drives and they will do a controlled stop, it will tell the CSMIO there is an E-Stop and a fraction of a second later the Enables are taken away from the servo drives.
The CSMIO is always powered as long as the computer is on.
The logic of the servo drives is always powered as long as the computer is on.
The power stage of the servos and the safety relay are powered when I press the start button.
Enables are via Mach to safety relay and can only get to the drive if there is no E-Stop condition or faults on any drives and Mach can not be taken out of Reset under the same circumstances.
There are additional fault signals from the servo drives which go to the CSMIOs integral Servo Fault inputs.
Hood